package main

import (
    "fmt"
    "io"
    "net/http"
    "os"
)

func main() {
    // 文件url需要修改成目标地址
    fileUrl := "http://asdlkskldko90/adk/asdlks/kajsd=?lksadklko&jmasdn1928="
    err := DownloadFile("22.mp4", fileUrl)
    if err != nil {
        panic(err)
    }
    fmt.Println("Downloaded: " + fileUrl)
}

// DownloadFile will download a url to a local file. It's efficient because it will
// write as it downloads and not load the whole file into memory.
func DownloadFile(filepath string, url string) error {

    // Get the data
    resp, err := http.Get(url)
    if err != nil {
        return err
    }
    defer resp.Body.Close()

    // Create the file
    out, err := os.Create(filepath)
    if err != nil {
        return err
    }
    defer out.Close()

    // Write the body to file
    _, err = io.Copy(out, resp.Body)
    return err
}

执行：

go run main.go

查看下载文件：

root@ubuntu:/tmp/zz# ll
total 1972
-rw-r--r-- 1 root root 3949617 Feb  4 11:06 22.mp4
-rw-r--r-- 1 root root    1341 Feb  4 11:00 main.go
root@ubuntu:/tmp/zz#